Scientists Create “Off-the-Shelf” Cartilage That Safely Guides the Body To Regrow Bone

A new study shows that engineered, cell-free cartilage can safely support bone regeneration without provoking immune rejection.

New research suggests it may be possible to repair major bone damage using a tissue implant that contains no living cells.

By relying on the body’s own repair machinery, the approach aims to encourage new bone growth while avoiding the kind of immune reaction that can complicate transplants. The findings, published in PNAS, clear several key hurdles needed to move toward the first clinical studies in humans.

A different idea for bone repair

Serious bone and skeletal injuries can leave people with lasting pain and reduced mobility, especially when the body cannot replace large amounts of missing tissue. That situation can arise after cancer-related bone removal, advanced joint diseases such as rheumatoid arthritis and osteoarthritis, or severe infections. In those cases, surgeons often turn to bone grafts, but today’s options can be limited and demanding.

The team at Lund University in Sweden reports a tissue-engineering strategy designed to work more like an “instruction manual” than a traditional transplant. Instead of implanting living cells, the researchers created a cartilage-based structure that is deliberately cell-free.

In animal testing, the implant supported bone repair without provoking strong immune responses, a sign that it could be safer and more broadly usable than approaches that depend on a patient’s own cells.

Why “off-the-shelf” matters

An estimated two million people worldwide may need bone tissue transplants each year. Many current methods rely on tissue or cells taken from the patient, which can mean added procedures, higher costs, and results that vary from one person to another. The Lund group is aiming for a more standardized alternative that could be produced ahead of time, stored, and used when needed.

“Patient-specific grafts are both costly and time-consuming and do not always succeed. A universal approach in tissue engineering, with a reproducible manufacturing process, offers major advantages. In our study, we present just such a method and demonstrate important advances toward a non-patient-specific technology,” says Alejandro Garcia Garcia, associate researcher in molecular skeletal biology at Lund University.

How a cell-free implant can still “communicate” with the body

In the study, researchers first grew cartilage in the lab, then removed the cells through decellularisation. What remains is the extracellular matrix, i.e., the natural supportive framework that tissues build around cells. Importantly, this matrix is not just structural. It can also hold biochemical cues.

The remaining cartilage structure retains embedded growth factors, which can help signal the body’s own cells to migrate in, begin rebuilding, and gradually replace the scaffold with new bone tissue. In simple terms, the implant provides a stable template plus biological instructions, then lets the patient’s body do the rest.

“The cartilage structure we have developed is based on stable, well-controlled, and reproducible cell lines, and can stimulate bone formation without triggering strong immune reactions. We show that it is possible to create a ready-made, so-called ‘off-the-shelf’ graft that interacts with the immune system and can repair large bone defects. Because the material can be produced in advance and stored, we see this as an important step toward future clinical use of human bone tissue transplants,” says Paul Bourgine, who led the study. He is an associate professor and researcher in molecular skeletal biology at Lund University.

Next step – scaling up and standardising

This method means that the cartilage structure can be manufactured in advance and used for many different patients, without the need for customization for each individual. The next step is to test the method in humans and to plan for scaling up and standardizing the manufacturing process.

“The next step involves deciding which types of injuries to test this on first, such as severe defects in long bones of the arms and legs. At the same time, we need to develop the documentation required for ethical review and regulatory approval to conduct clinical trials. In parallel, we are establishing a manufacturing process that can be carried out on a larger scale while maintaining the same high level of quality and safety every time,” says Alejandro Garcia Garcia.

Reference: “Engineered and decellularized human cartilage graft exhibits intrinsic immunosuppressive properties and full skeletal repair capacity” by Alejandro Garcia Garcia, Sujeethkumar Prithiviraj, Deepak Bushan Raina, Tobias Schmidt, Sara Gonzalez Anton, Laura Rabanal Cajal, David Hidalgo Gil, Magnus Tägil, Axel Hyrenius-Wittsten, Madelene W. Dahlgren, Robin Kahn and Paul E. Bourgine, 9 January 2026, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2507185123

Funding: The Knut and Alice Wallenberg Foundation, Region Skåne, European Research Council, The Swedish Research Council, The Swedish Cancer Society, Sten K Johnson Foundation, IngaBritt and Arne Lundberg Research Foundation

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